Method and Apparatus for Monitoring and Troubleshooting of HVAC Equipment

ABSTRACT

A method for monitoring operational conditions of an HVAC unit and providing preventive maintenance alerts and/or troubleshooting instructions using an ordered set of causes for sensed parameters by monitoring parameters of the HVAC unit with sensors, collecting real time information and transmitting the data and analyzing the data with a processor and comparing it to a list of pre-determined data set points to determine variances from the set points and identification of one or more maintenance alerts and/or trouble events associated with variances, matching them to at least one of the events, displaying instructions to a user for resolving the event in a descending order determined by the processor of the most likely causes along with an associated solution for each cause, and providing a pre-failure solution from the stored set of instructions based on analysis of the stored data and timed sensor values.

CROSS REFERENCE TO RELATED APPLICATIONS

This application takes priority from a provisional application for patent entitled “Method and Apparatus For Monitoring and Troubleshooting of HVAC Equipment” having Ser. No. 62/061,765 filed Oct. 9, 2014 and is incorporated as if fully set forth herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

DESCRIPTION OF ATTACHED APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

This invention relates generally to the field of system maintenance and more specifically to a Method and Apparatus For Monitoring and Troubleshooting of HVAC Equipment.

BRIEF SUMMARY OF THE INVENTION

The primary advantage of the invention is to provide a system for monitoring heating and cooling systems and machinery on a real time basis and provide troubleshooting guides to users based on sensed parameters.

Another advantage of the invention is to provide real time data on the performance of heating, ventilation, air conditioning, and refrigeration systems.

Another advantage of the invention is to provide sensors that shall be integrated into a programmable logic controller (PLC) which shall process the data and establish alarm levels and trigger points for preventive maintenance and troubleshooting activities.

Another advantage of the invention is to provide a customer multiple interfaces including a local HMI and/or provide the ability to tie into a customer's DCS or SCADA system.

Other objects and advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention.

FIG. 1 is a block diagram showing system components according to a preferred embodiment of the invention.

FIG. 2A through 2F are a schematic diagram of wiring to an HVAC system according to a preferred embodiment of the invention.

FIGS. 3A through 3I are display screens for event information according to a preferred embodiment of the invention.

FIGS. 4A through 4H are display screens for event information according to a preferred embodiment of the invention.

FIGS. 5A through 5G are display screens for event information according to a preferred embodiment of the invention.

FIGS. 6A through 6I are display screens for event information according to a preferred embodiment of the invention.

FIGS. 7A through 7I are display screens for event information according to a preferred embodiment of the invention.

FIGS. 8A through 8G are display screens for event information according to a preferred embodiment of the invention.

FIGS. 9A through 9I are display screens for event information according to a preferred embodiment of the invention.

FIGS. 10A through 10H are display screens for event information according to a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Detailed descriptions of the preferred embodiment are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for later filed claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or manner.

The HVAC Monitoring system of the present invention in a preferred embodiment is a strap on system that provides real time data on the performance of heating, ventilation, air conditioning, and refrigeration systems. Additionally, the system may apply to filtration, purge, and pressurization systems. The core of the system is the instrumentation of the equipment using various sensing methods that shall include discrete (on/off) and analog (flow, humidity, pressure and temperature) sensing systems. These sensors are integrated into a programmable logic controller (PLC) which processes the data and establishes alarm levels and trigger points for maintenance activities. The system shall provide for multiple customer interfaces including a local HMI and/or provide the ability to tie into a customer's DCS or SCADA system. Additionally, the system shall be designed to be integrated with an SAS designed SCADA system. Further, the system has various troubleshooting alarms and preventive maintenance events for users to efficiently manage problems at an early stage. The alarms and events provide a series of displayed solutions to a particular problem enabling the user to fix the system without third party intervention.

As is readily apparent, multiple HVAC units may be monitored by this system and present warnings or trigger events to a user from a number of units. The display information can be configured to respond to a plurality of units being monitored and supply troubleshooting instructions for each of the monitored units.

FIG. 1 shows a block diagram of the interaction of a preferred embodiment of the present invention with a monitored system. PLC 2 receives raw sensor data from the monitored HVAC system and Sensing Package 4 and processes the date into useable digital data. PLC 2 establishes alarm and preventive maintenance after hours or “PM” levels as well. HVAC Unit and Sensing Package 4 is connected to the various equipment and sends the raw data to PLC 2. PLC 2 in turn sends data to HMI 6 for local display of all monitored points and alarms. PLC 2 may also send data to a customer designed or custom DCS or SCADA system 8 for graphic display of all monitored point and alarms.

A preferred embodiment of the system has a series of sensors including, but not limited to, system monitoring sensors for the following parameters:

Airflow/Differential Pressure;

Discharge/Supply Air Flow;

Fresh Air/Stack Air Flow;

Room Pressure (before filter);

Stack Pre-Filter Pressure; and

Stack Post-Filter Pressure.

The system may also have motor sensors including the following:

Evaporator Motor Current Transducer (CT);

Condenser Motor Current Transducer (CT);

Purge/Pressurization Motor Current Transducer (CT);

Compressor Current Transducer (CT); and

Heating Element Current Transducer (CT).

The system may additionally have refrigerant system sensors including the following:

Suction Pressure(s);

Suction Temperature(s);

Liquid Line Pressure(s);

Liquid Line Temperature(s);

Discharge Line Temperature(s); and

Discharge Line Pressure(s).

Additionally the system may have general performance sensors including the following:

Room/Return Air Temperature(s)/RH;

Discharge/Supply Air Temperature;

Discharge/Supply Air RH;

Room/Return Air Temperature/RH;

Fresh Air Temperature/Fresh Air RH;

Unit Incoming Voltage;

Unit Incoming Phase (dry contact); and

Unit Total Current.

Turning now to FIGS. 2A through 2F, a schematic 10 of a representative wiring diagram of a monitoring system of the present invention is shown. Panel 12 includes a programmable logic array 11 and display 13 for processing data collected from the HVAC system being monitored. Panel 12 is connected by Ethernet cable 14 to Ethernet switch 26. Panel 12 is powered through lines 16 through junction block 18 which in turn is connected to fuse time delay 20, connected to power supply 22 which is in turn connected via fuse time delay 24 to a power grid or electrical outlet.

Ethernet switch 26 is interconnected via cable 28 which connects to Ethernet adapter 38 via connecting identifier A from FIG. 4A to 4B. A series of input modules 40, 44, 46, 48, 50, 52, and 54 are connected as further described below. Power is supplied to Ethernet adapter 38 via lines 30, as well as supplied to strips 56 and 58.

Input module 40 is connected via identifier D by a ribbon cable 70 which connects to terminal block module 72. IDEC modules 74 are connected to strip 76 which in turn are connected to system shutdown signal to evaporator 78, blower signal 80, stage 1 cooling signal 81, stage 1 heating signal 82, stage 1 condenser fan cycle signal 84 and common side of control power transformer 86.

Ethernet cable 32 via identifier C is connected to an automation system terminal block module 60 which is in turn connected via Ethernet cable 62 to a second automation system terminal block module 64 connected by Ethernet cable 66 to power monitoring module 68.

FIG. 2B shows Ethernet cable 34, via identifier D connected to D on FIG. 4C and third terminal block module 72 as previously described.

FIG. 2 shows stage 1 discharge line temperature sensor 94, stage 1 liquid line temperature sensor 96 and stage 1 suction line temperature sensor 98 each connected to strip 92 and in turn connected to terminal block module 88 which is in turn connected via ribbon cable 36 to input module 40. Data from temperature sensors 94, 96 and 98 are communicated by digital signal back to panel 12 and stored in memory.

In similar fashion, supply air humidity/temperature transmitter 114, return air humidity/temperature transmitter 116 and fresh air intake humidity/temperature transmitter 118 are connected lines through strip 112 via identifier F to input modules 46 and 48 for transmission of digital data to panel 12 for further processing.

FIG. 2F shows a number of sensors according to a preferred embodiment of the invention. Heater current sensor 138, evaporator motor #1 current 140, condenser motor #1 current 142 and stage 1 compressor current 144 are transmitted via strip 136 and 134 to input modules 52 and 54 for transmission of sensed information to panel 12 as described hereinabove.

Similarly, fresh air post-filter sensor 146, fresh pre-filter sensor 148, building pressure sensor 150, fresh air intake flow sensor 152 and supply air flow sensor 154 are connected to these functions on the HVAC unit to sense and transmit.

Each of the foregoing sensors obtain real time data from the various sensed parameters and deliver via digital signal that data to the processor in panel 12. The data is compared to pre-set data points stored in memory.

Equipment types that may be monitored are set forth in Tables 1A and 1B. Tables 1A and 1B have common first two columns and present data for each of the Equipment Tag Names listed. Table 1 shows a sample instrument list of different manufacturer's products that may be sensed and monitored. Each is provided a unique Tag name which pertains to various characteristics of the system including instrument type, service description, manufacturer, model number, system provided part number, input/output type (which may be discrete or analog), signal type, power supply, certification, HAZLOC, Calibration ranges lo and hi, Engineering units, and other data.

TABLE 1A Table One (A) Instrument Service Model SAS IO Signal Power Tag Name Type Description Manufacturer Number Part # Type Type Supply XS_10001 N/A System N/A N/A N/A DI 24 24 Shutdown Signal VDC VDC XS_10002 N/A Evaporator N/A N/A N/A DI 24 24 Blower Signal VDC VDC XS_10003 N/A Stage 1 Cooling N/A N/A N/A DI 24 24 Signal VDC VDC XS_10004 N/A Stage 2 Cooling N/A N/A N/A DI 24 24 Signal VDC VDC XS_10005 N/A Stage 1 Heating N/A N/A N/A DI 24 24 Signal VDC VDC XS_10006 N/A Stage 2 Heating N/A N/A N/A DI 24 24 Signal VDC VDC XS_10007 N/A Stage 1 Condenser N/A N/A N/A DI 24 24 Fan Cycle Signal VDC VDC XS_10008 N/A Stage 2 Condenser N/A N/A N/A DI 24 24 Fan Cycle Signal VDC VDC XS_10009 N/A Pressurization N/A N/A N/A DI 24 24 System Enable VDC VDC Signal RTD_10010 RTD Stage 1 Discharge Turck TP-203A-CF- 100726 AI RTD N/A Line Temperature H1141-L100 RTD_10011 RTD Stage 1 Liquid Turck TP-203A-CF- 100726 AI RTD N/A Line Temperature H1141-L100 RTD_10012 RTD Stage 1 Suction Turck TP-203A-CF- 100726 AI RTD N/A Line Temperature H1141-L100 RTD_10013 RTD Stage 2 Discharge Turck TP-203A-CF- 100726 AI RTD N/A Line Temperature H1141-L100 RTD_10014 RTD Stage 2 Liquid Turck TP-203A-CF- 100726 AI RTD N/A Line Temperature H1141-L100 RTD_10015 RTD Stage 2 Suction Turck TP-203A-CF- 100726 AI RTD N/A Line Temperature H1141-L100 HT_10016 Humidity Supply Air Minco AH439D 100831 AI 4-20 24 Transmitter Humidity 1S20EN T2 mA VDC Transmitter TT_10017 Temperature Supply Air Minco AH439D 100831 AI 4-20 24 Transmitter Temperature 1S20EN T2 mA VDC Transmitter HT_10018 Humidity Return Air Minco AH439D 100831 AI 4-20 24 Transmitter Humidity 1S20EN T2 mA VDC Transmitter TT_10019 Temperature Return Air Minco AH439D 100831 AI 4-20 24 Transmitter Temperature 1S20EN T2 mA VDC Transmitter HT_10020 Humidity Fresh Air Intake Minco AH439D 100831 AI 4-20 24 Transmitter Humidity 1S20EN T2 mA VDC Transmitter TT_10021 Temperature Fresh Air Intake Minco AH439D 100831 AI 4-20 24 Transmitter Temperature 1S20EN T2 mA VDC Transmitter PT_10022 Pressure Stage 1 Discharge Johnson P499AC 109086 AI 4-20 24 Transmitter Line Pressure Controls P-107K mA VDC PT_10023 Pressure Stage 1 Liquid Johnson P499AC 109086 AI 4-20 24 Transmitter Line Pressure Controls P-107K mA VDC PT_10024 Pressure Stage 1 Suction Johnson P499AC 109086 AI 4-20 24 Transmitter Line Pressure Controls P-107K mA VDC PT_10025 Pressure Stage 2 Discharge Johnson P499AC 109086 AI 4-20 24 Transmitter Lane Pressure Controls P-107K mA VDC PT_10026 Pressure Stage 2 Liquid Johnson P499AC 109086 AI 4-20 24 Transmitter Line Pressure Controls P-107K mA VDC PT_10027 Pressure Stage 2 Suction Johnson P499AC 109086 AI 4-20 24 Transmitter Line Pressure Controls P-107K mA VDC PDT_10028 Differential Building Dwyer MS2-W102- 100733 AI 4-20 24 Pressure Pressure DP LCD mA VDC Transmitter PDT_10029 Differential Fresh Air Dwyer MS2-W102 100733 AI 4-20 24 Pressure Intake Flow DP LCD mA VDC Transmitter PDT_10030 Differential Supply Air Dwyer MS2-W102- 100733 AI 4-20 24 Pressure Flow DP LCD mA VDC Transmitter PDT_10031 Differential Fresh Air Dwyer MS2-W102- 100733 AI 4-20 24 Pressure Post-Filter DP LCD mA VDC Transmitter PDT_10032 Differential Fresh Air Dwyer MS2-W102- 100733 AI 4-20 24 Pressure Pre-Filter DP LCD mA VDC Transmitter CT_10033 Current Stage 1 Compressor Dwyer LTTJ-020 100720 AI 0-10 24 Transducer Current VDC VDC CT_10034 Current Stage 2 Compressor Dwyer LTTJ-020 100720 AI 0-10 24 Transducer Current VDC VDC CT_10035 Current Condenser Motor Dwyer LTTJ-020 100720 AI 0-10 24 Transducer #1 Current VDC VDC CT_10036 Current Condenser Motor Dwyer LTTJ-020 100720 AI 0-10 24 Transducer #2 Current VDC VDC CT_10037 Current Evaporator Motor Dwyer LTTJ-020 100720 AI 0-10 24 Transducer #1 Current VDC VDC CT_10038 Current Evaporator Motor Dwyer LTTJ-020 100720 AI 0-10 24 Transducer #2 Current VDC VDC CT_10039 Current Evaporator Motor Dwyer LTTJ-020 100720 AI 0-10 24 Transducer #3 Current VDC VDC CT_10040 Current Stage 1 Heater Dwyer LTTJ-020 100720 AI 0-10 24 Transducer Current VDC VDC CT_10041 Current Stage 2 Heater Dwyer LTTJ-020 100720 AI 0-10 24 Transducer Current VDC VDC CT_10042 Current Pressurization Dwyer LTTJ-020 100720 AI 0-10 24 Transducer Motor #1 Current VDC VDC CT_10043 Current Pressurization Dwyer LTTJ-020 100720 AI 0-10 24 Transducer Motor #2 Current VDC VDC

TABLE 1B Table One (B) Instrument Certifi- HAZ- Calibration Calibration Engineering Tag Name Type cation LOC Range Lo Range Hi Units Rack Slot Point XS_10001 N/A N/A 0 1 N/A 1 1 1 XS_10002 N/A N/A 0 1 N/A 1 1 2 XS_10003 N/A N/A 0 1 N/A 1 1 3 XS_10004 N/A N/A 0 1 N/A 1 1 4 XS_10005 N/A N/A 0 1 N/A 1 1 5 XS_10006 N/A N/A 0 1 N/A 1 1 6 XS_10007 N/A N/A 0 1 N/A 1 1 7 XS_10008 N/A N/A 0 1 N/A 1 1 8 XS_10009 N/A N/A 0 1 N/A 1 1 10 RTD_10010 RTD −22 662 ° F. 1 3 4 RTD_10011 RTD −22 662 ° F. 1 3 5 RTD_10012 RTD −22 662 ° F. 1 3 3 RTD_10013 RTD −22 662 ° F. 1 3 4 RTD_10014 RTD −22 662 ° F. 1 3 5 RTD_10015 RTD −22 662 ° F. 1 3 6 HT_10016 Humidity 0 100 % 1 4 1 Transmitter TT_10017 Temperature −20 140 ° F. 1 4 2 Transmitter HT_10018 Humidity 0 100 % 1 4 3 Transmitter TT_10019 Temperature −20 140 ° F. 1 4 4 Transmitter HT_10020 Humidity 0 100 % 1 4 2 Transmitter TT_10021 Temperature −20 140 ° F. 1 4 6 Transmitter PT_10022 Pressure CE/ CID2 0 750 PSI 1 4 7 Transmitter UL PT_10023 Pressure CE/ CID2 0 750 PSI 1 4 8 Transmitter UL PT_10024 Pressure CE/ CID2 0 750 PSI 1 5 1 Transmitter UL PT_10025 Pressure CE/ CID2 0 750 PSI 1 5 2 Transmitter UL PT_10026 Pressure CE/ CID2 0 750 PSI 1 5 3 Transmitter UL PT_10027 Pressure CE/ CID2 0 750 PSI 1 5 4 Transmitter UL PDT_10028 Differential CE 0 1250 Pascals 1 5 5 Pressure Transmitter PDT_10029 Differential CE 0 1250 Pascals 1 5 6 Pressure Transmitter PDT_10030 Differential CE 0 1250 Pascals 1 5 7 Pressure Transmitter PDT_10031 Differential CE 0 1250 Pascals 1 5 8 Pressure Transmitter PDT_10032 Differential CE 0 1250 Pascals 1 6 1 Pressure Transmitter CT_10033 Current 0 100 Amperes 1 7 1 Transducer CT_10034 Current 0 100 Amperes 1 7 2 Transducer CT_10035 Current 0 100 Amperes 1 7 3 Transducer CT_10036 Current 0 100 Amperes 1 7 4 Transducer CT_10037 Current 0 100 Amperes 1 7 5 Transducer CT_10038 Current 0 100 Amperes 1 7 6 Transducer CT_10039 Current 0 100 Amperes 1 7 7 Transducer CT_10040 Current 0 100 Amperes 1 7 8 Transducer CT_10041 Current 0 100 Amperes 1 7 1 Transducer CT_10042 Current 0 100 Amperes 1 7 2 Transducer CT_10043 Current 0 100 Amperes 1 7 3 Transducer

Each of the sensors identified in FIG. 2, may have various set points and acceptable ranges. These set points and ranges are relatable to one or more Events which the system generates for troubleshooting. Table 2 sets forth a list of sensors, acceptable parameter rates in Hi SP and Lo SP columns and Events that pertain to those sensed parameters.

TABLE 2 IO Signal Power Engineering Item Description Type Type Supply Units Hi SP Lo SP Events Calculated Superheat N/A Calc N/A ° F. 20 10 1-6, 9-14 Calculated Subcooling N/A Calc N/A ° F. 20 10 1-4, 7-12, 15, 16 Compressor Current AI 4-20 24 % AMPERES 125 25 17, 18 (Note 1) mA VDC Condenser/Evaporator/ AI 4-20 24 % AMPERES 90 25 19-23, Purge Motor Current mA VDC 26, 27 (Note 2) Heater Current AI 4-20 24 % AMPERES 125 75 24, 25 (Note 3) mA VDC Room/Building/Shelter/ AI 4-20 24 IWC 0.25  0.1 30 Enclosure/Cabinet mA VDC Pressure Room/Building/Shelter/ AI 4-20 24 ° F. 85 55 31, 77 Enclosure/Cabinet mA VDC Temperature Discharge Air AI 4-20 24 ° F. 192 N/A 32 Temperature mA VDC Incoming Voltage AI 4-20 24 % VOLTS 110 90 33, 73-76 (Note 4) mA VDC Contactor Cycle Limit N/A Calc N/A COUNTS 100000 N/A 40-50 Pre-Filter AI 4-20 24 IWC 0.2 N/A 78 Differential Pressure mA VDC Post-Filter AI 4-20 24 IWC 0.2 N/A 79 Differential Pressure mA VDC Discharge Refrigerant AI 4-20 24 PSI 575 N/A 34, 35 Pressure (Note 5) mA VDC Suction Refrigerant AI 4-20 24 PSI N/A 20 36, 37 Pressure (Note 6) mA VDC Fresh Air Flow AI 4-20 24 % CFM 120 80 28 (NOTE 7) mA VDC Discharge Air Flow AI 4-20 24 % CFM 120 80 29 (NOTE 8) mA VDC (Note 1): COMPRESSOR CURRENT ALARM SETPOINTS ARE EXPRESSED AS A PERCENTAGE OF COMPRESSOR'S RATED RUN LOAD AMPS (RLA). (Note 2): MOTOR CURRENT ALARM SETPOINTS ARE EXPRESSED AS A PERCENTAGE OF MOTOR'S RATED FULL LOAD AMPS (FLA). (Note 3): HEATER CURRENT ALARM SETPOINTS ARE EXPRESSED AS A PERCENTAGE OF HEATER'S CALCULATED CURRENT BASED ON ITS RATED WATTAGE. (Note 4): VOLTAGE ALARM SETPOINTS ARE EXPRESSED AS A PERCENTAGE OF RATED SYSTEM VOLTAGE. (Note 5): DISCHARGE LINE PRESSURE ALARM SETPOINTS ARE DIFFERENT FOR EACH REFRIGERANT TYPE. Table 2 (Note 5): SUCTION LINE PRESSURE ALARM SETPOINTS ARE DIFFERENT FOR EACH REFRIGERANT TYPE. (NOTE 7): FRESH AIR FLOW RATE IS DEPENDENT ON SYSTEM DESIGN PURGE AND/OR BUILDING LEAKAGE REQUIREMENTS. (NOTE 8): DISCHARGE AIR FLOW RATE IS DEPENDENT ON REFRIGERATION TONNAGE.

So for example, compressor current set points are shown as a percentage of the compressor's rated run load in amperes. Each item that is being sensed has high and low parameters that when triggered feed information into the processor to determine which of the Events are occurring. For example, Heater Current is expressed in amperes and if it deviates from the acceptable range by 125% or 75%, it will produce a display of Event 24 or 25 depending on additional data. Then Event 24 will display on the screen and provide the user with troubleshooting information.

FIGS. 3 through 10 show troubleshooting information displays for various events that may be monitored by the system of the preferred embodiment of the invention. Various sensing parameters will be processed into individual actionable events for the purpose of ease of interpretation and maintenance. For example, in FIG. 3A, Event 01 is a tag name given to the event description—“Stage 1 high superheat and low subcool detected,” which is computed from suction and liquid line pressures and temperatures. Each event is similarly provided a unique tag for processing by the PLC and system.

For each event, a preventive maintenance alert and/or troubleshooting guide is provided as exemplified below FIGS. 3 through 10.

Monitoring/Alarm Functions are provided to analyze Airflow/Pressure. Using analog data from airflow and pressure sensors allows for the following to be monitored: dirty filter monitoring; dirty coil monitoring (indicated by refrigerant pressures); statement of unit performance; total delivered tons (calculated); total delivered CFM to conditioned space (measured); total return air CFM (calculated); total fresh air CFM (measured); and the number of air changes per hour (requires user input of building parameters).

In a preferred embodiment, motor ON/OFF and current transducers are provided. These permit monitoring of the motor current using a CT (single leg) of all motor driven components and allows for display of all components that are on and off; the motor current using a CT (single leg) of all motor driven components and a relay on the contactor can display an alarm if the motor is called for, but not engaged; the motor current using a CT (single leg) of all motor driven components can determine the ON/OFF status and allows for run timers to be established for each component which can trigger maintenance activities (such as greasing motors or PM checks); the motor current using a CT (single leg) of all motor driven components can determine the run status and establishes the number of starts on the component which can trigger maintenance activities (i.e. excessive motor or compressor starts per hour or contactor life); and the motor current using a CT (single leg) of all motor driven components can allow for comparison against nameplate FLA vs. actual running current. When a component draws more amps than FLA plus service factor, a maintenance activity will be triggered.

The Refrigerant System is monitored by monitoring the pressure and temperature of refrigerant charge which allows for the calculation and display of each system's superheat and subcool to indicate refrigeration system health and allow for scheduled maintenance and, if necessary, shutdown for repair if a leak is found. Superheat and subcool levels will be displayed and alarms generated on out of range conditions. For example, high refrigerant discharge pressures can indicate condenser blockage, condenser fan problems, or dirty condenser coil; low refrigerant suction pressures can indicate evaporator blockage, evaporator fan problems, coil icing, dirty return air filter, or dirty evaporator coil.

The Heater System may be monitored by monitoring the current draw of one leg of the heater wiring and the discharge temperature. The unit's incoming voltage can also allow for the display of each heater stage status and total delivered heating kW to the space.

General Performance can be monitored by measuring the temperature and RH of the conditioned space and allows for the display of the unit's general performance and can trigger alarms when temperatures and RH are out of range. Table 2 shows a list of typical parameters and the set points being measured against. For each parameter being sensed, there are set points of a preferred operating range as shown in Table 2. If the processor detects a sensed data that is different than pre-determined settings, it enters that data into the PLC to determine if it alone, or in combination with other sensed signals, triggers an event. For example, certain events are the result of a deviation from two sensor readings. Event 1 is triggered by a sensor reading of the calculated superheat being too high or low and the calculated subcooling being too high or low as set forth in Table 2. In other situations, Event 34 is triggered by the discharge refrigerant pressure being out of a pre-determined range.

Data Gathering/Processing and Sensor Data Gathering may be monitored as well.

The sensor data shall be gathered into a single PLC. The PLC will gather all analog and digital sensor data and process it into useful data.

Sensor Processing is accomplished with a PLC program shall be written to take raw data and establish the following:

Filter Δp monitoring and dirty filter alarm levels;

Calculated Return Airflow with alarm (low and high);

Fresh Air Airflow with alarm (low and high);

Discharge/Supply Airflow with alarm (low and high);

Number of Air Changes calculation with alarm (low and high);

Supply Air Pressure with alarm level (high);

Room Pressure with alarm level (low and high);

Run time for each component with PM levels after established threshold has been met;

Number of ON/OFF cycles for each contactor component with PM levels after established threshold has been met;

Motor current display with alarm levels based on RLA or FLA (plus service factor) input;

Refrigerant system superheat and subcool calculation and display with alarm levels (high and low);

Iced/Blocked/Dirty Coil alarms based on refrigerant pressures;

Heat system ON/OFF with unit voltage and heater current to calculate actual delivered kW to space; and

Temperature sensor reporting and calculation of actual delivered capacity in kW, Btu/Hr and tons.

Alarms shall be established when delivered air temperatures are out of range.

Local Human Machine Interface “HMI” Display may have the following displays:

Filter Δp gauges with red zones for alarm levels and dirty filter alarm ON/OFF;

Return Airflow Gauge with red zones for alarm levels and low return air alarm ON/OFF;

Fresh Air Airflow Gauge with red zones for alarm levels (low and high) and low and high alarms;

Discharge/Supply Airflow Gauge with red zones for alarm levels (low and high) and low and high alarms;

Number of Air Changes display with alarm level for low and high number of air changes;

Room Pressure gauge with red zone for high and low levels with high and low alarm indicators;

Run time display for each component with PM level indicators;

Number of ON/OFF cycles display for each component with PM levels indicator. Alarm displayed if any motor/heater contactor is called for, but not engaged;

Motor current draw display for each motor and with high alarm level indicator;

Refrigerant system superheat and subcool display with high and low alarm levels;

Refrigerant system gauges with out of range indicators (iced, blocked or dirty coil);

Heat system ON/OFF display with total current display and display of actual delivered kW. Alarm displayed if heater contactor is called for, but not engaged;

Temperature reading displays with normal alarm levels of out of range values. Display of actual delivered capacity in kW, Btu/Hr and/or tons;

Trending display for all sensors;

Historical display of all sensors up to a pre-determined time period; and

Alarm log for all alarms and preventive maintenance alerts.

In certain cases, the system processor will analyze trending data and check against pre-determined set points for activation of Event and troubleshooting or maintenance instructions. For example, if the system aggregates data showing a temperature sensor reading downward over a specified period of time, it may indicate a potential problem and based on that trend, the processor will match to a pre-determined event and generate an appropriate display for resolution.

FIGS. 3 through 10 show a number of Events triggered by various combinations of sensed data from the various sensors employed in the system. Each Event listing is stored in memory and tied to a set of instructions or troubleshooting guides that responds to alarms and provides maintenance advice when various factors reach certain milestones or otherwise trigger an Event. When the Event occurs, it matches the stored instructions with one or more sensed data readings to display the Event and troubleshooting guide for the user to review and execute. A particular Event may have several solutions or a series of solutions that may be tried one after the other to solve the problem.

Each Event is identified by Title, Possible Causes, and Recommended Solutions to generate a display of the particular Event in response to the pre-determined set points in comparison to the sensed data.

For example, as shown in FIG. 10H, Event 98 illustrates a continuous trend analysis, while the amperage has not exceeded limits, the uptrend demonstrate a deteriorating motor and we recommend action before failure. Event 99 illustrates a frequent occurrence within a specified amount of time. In this case, frequent voltage irregularities call for either a source fix, or a power quality enhancement on the load side. Event 100 illustrates a comparison of two identical and redundant units serving a common air conditioned space. One operating at lower efficiency than the other calls for maintenance checks. Event 101 illustrates a timed preventive maintenance event even in the absence of a sensor variance, recommended for continued smooth operation.

Certain Events may be triggered for maintenance purposes before an actual problem arises. In this case, sensor variances or trends may be analyzed against pre-determined points and matched to a display of an Event. Similarly, maintenance events may be triggered based on run time independent of any sensed data or trends and appropriate display triggered for the user. As previously discussed, Events may be configured for any of a variety of sensors and conditions with appropriate troubleshooting or maintenance solutions stored in memory for retrieval and display to a user.

While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the later filed claims. 

1-18. (canceled)
 19. A method for monitoring operational conditions of a heating ventilation and air conditioning (HVAC) unit and providing preventive maintenance alerts and/or troubleshooting instructions using an ordered set of causes for sensed parameters comprising the steps of: monitoring one or more operational parameters of the HVAC unit with a plurality of sensors; collecting real time operational information from the sensors in a data acquisition device and transmitting the data to a storage device; analyzing the real time data with a processor and comparing it to a list of pre-determined data set points stored in memory pertaining to one or more of the parameters to determine variances from the data set points and identification of one or more pre-determined maintenance alerts and/or trouble events associated with one or more of the variances; matching a set of preventative maintenance alerts and troubleshooting instructions stored in the storage device pertaining to the events to at least one of the events; displaying the instructions to a user for resolving the event in a descending order determined by the processor of the most likely causes along with an associated solution for each cause; and providing a pre-failure solution from the stored set of instructions based on analysis of the stored data and timed sensor values.
 20. The method according to claim 19, wherein each portion of the operational information is directed to a specific operational parameter of the asset.
 21. The method according to claim 19, wherein the processor analyzes the stored data with trending analysis and failure prediction based on a timed sensed value trend and provides a pre-failure solution from the stored set of instructions.
 22. The method according to claim 19, further comprising storage of a set of timed recommended preventive maintenance activities for the HVAC unit and maintenance activity log for reference and record.
 23. The method according to claim 19, wherein matching of the instructions to the sensed parameters is stored in a programmable logic array.
 24. The method according to claim 19, wherein the pre-determined data set points are based on a percentage deviation from a known quantity.
 25. The method according to claim 19, wherein the sensed parameters include real time preventive maintenance and troubleshooting monitoring.
 26. A method for monitoring operational conditions of a machine and troubleshooting using an ordered set of causes for sensed parameters comprising: sensing one or more operational parameters of the machine; collecting real time operational information from the sensors over a network and transmitting the data to a storage and processing device; analyzing with a processor the real time data and comparing it to a list of preferred data set points pertaining to each of the parameters to determine variances from the data set points and identification of one or more events associated with one or more of the variances; matching a set of preventative maintenance alerts and troubleshooting instructions stored in a storage device pertaining to the events to the troubleshooting instructions for at least one of the events; displaying a pre-failure solution from the stored set of instructions based on a trending analysis of the variances from the data set points based on a timed sensor value trend.
 27. The method of claim 26, wherein each of the portion of the operational information is directed to a respective one of the plurality of operational parameters.
 28. The method of claim 26, further comprising receiving user input based on the preventive maintenance alerts and/or troubleshooting displays.
 29. The method according to claim 26, wherein the plurality of sensors Preliminary Amendment page 8 include at least one from the group comprising measuring temperature, pressure, humidity, airflow, voltage, unit cooling capacity and current.
 30. The method according to claim 26, further comprising developing a preventive maintenance alerts and/or troubleshooting display list associated with the machine and enabling user input to the machine for configuration of the machine.
 31. The method according to claim 26, wherein the analyzing is based in part on calculating life expectancy of a component.
 32. The method according to claim 26 further comprising an alarm and/or event that activates when a deviation is determined to exist from the predetermined set points.
 33. A system for monitoring operational conditions of a heating ventilation and air conditioning (HVAC) unit and providing preventative maintenance alerts and/or troubleshooting instructions using an ordered set of causes for sensed conditions comprising: a plurality of sensors, including at least one from the group comprising pressure, temperature, humidity, air flow, voltage, machine capacity, and current provided to monitor one or more operational parameters of the HVAC unit; a data acquisition device for collecting real time operational information from the sensors and transmitting the data to a storage device; a programmable logic array for analyzing the real time data and comparing it to a set of pre-determined data points pertaining to one or Preliminary Amendment page 9 more of the parameters to determine variances from pre-determined values and identification of at least one preventative maintenance or troubleshooting event associated with one or more of the variances; a set of preventative maintenance alerts and/or troubleshooting instructions stored in the storage device pertaining to the events; a processor for matching one of the preventative maintenance alerts and/or troubleshooting instructions to at least one of the events; an alert to a user of one of the instructions at a time, rotating through a set of instructions for each event in an order determined by the processor showing the most likely cause to the least likely cause of the event along with associated solutions for each cause; and wherein the processor analyzes the stored data with trending analysis and failure prediction based on a timed sensor value trend and provides a pre-failure solution from the stored set of instructions.
 34. The system according to claim 33 comprising a supervisory system comprising: a plurality of data acquisition and storage devices for collection and storage of real time operational information from the sensors of multiple heating ventilation and air conditioning (HVAC) units; a processor for analyzing real time data from multiple HVAC units and comparing it to a list of pre-determined data set points pertaining to one or more of the parameters from one or more units to determine variances from pre-determined values and identification of one or more preventive Preliminary Amendment page 10 maintenance and/or troubleshooting events associated with one or more of the variances; a display of stored data on various compatible display devices; a processor for analyzing the pre-determined data with trending analysis and failure prediction based on timed sensor value trend and displaying the identified event to a user to provide a pre-failure solution from the stored events; a combined log stored in memory of maintenance alerts and troubleshooting events; and a combined log of maintenance and troubleshooting activities stored in memory for reference and record by the user.
 35. The system according to claim 33, wherein the pre-determined data set points are based on a percentage deviation from a known quantity.
 36. The system according to claim 33, wherein the preventative maintenance alert comprises prediction of component failure.
 37. The system according to claim 33, further comprising selective interconnection with multiple display devices.
 38. The system according to claim 33, wherein the pre-determined data set points are based on a percentage deviation from a known quantity 